Field of the Invention
The present invention relates to a metal oxide particle dispersion for manufacturing a particulate magnetic recording medium, a method of manufacturing a magnetic layer-forming composition of a particulate magnetic recording medium and a method of manufacturing a particulate magnetic recording medium.
Discussion of the Background
Magnetic recording media come in the forms of particulate magnetic recording media, which have a magnetic layer fabricated by coating a magnetic layer-forming composition—containing ferromagnetic powder and binder dispersed in solvent—on a nonmagnetic support, and magnetic recording media of the thin metal film type, in which ferromagnetic powder is deposited on a nonmagnetic support to form a film. From the perspectives of productivity and general versatility, particulate magnetic recording media are known to be superior. Hereinafter, unless specifically stated otherwise, the term “magnetic recording medium” will be used to refer to particulate magnetic recording media.
In a particulate magnetic recording medium, metal oxide particles, which are a type of nonmagnetic powder, are often employed as a component of the magnetic layer (for example, see Japanese Unexamined Patent Publication (KOKAI) No. 2013-131285 or English language family member US2013/130064A1, which are expressly incorporated herein by reference in their entirety). By causing metal oxide particles to suitably protrude from the surface of the magnetic layer, abrasiveness that removes foreign material (head deposits) that have adhered to the magnetic head can be imparted to the surface of the magnetic layer, the coefficient of friction during sliding of (contact between) the surface of the magnetic layer and the magnetic head can be reduced, and running stability can be enhanced.